Enzymes in Physiology Flashcards
Why are enzymes important for pharmacy?
Involved in biochemical reactions Reactions needed for survival * component of pharmaceutical management of disease in patients Used diagnostically Used therapeutically
What are functions of enzymes?
Weaken bonds in reactions May provide nucleophiles Biological catalyst Active site Provide suitable environment Position reactants correctly May provide acid/base catalyst
What does enzymes NOT change?
Eqm position
What is an active site?
Region within enzyme that fits the shape of substrate molecules
What happens when enzyme and substrate bind?
Amino acid side chains align to bind to substrate through H-bonding Products released (no longer fit active site)
Describe lock + key model
Rigid active site
Fit between active site + substrate = exact
Enzyme-substrate complex formed
Product different shape to substrate
Enzyme free to bind to another substrate when product released
Describe induced fit
Active site flexible + can change
Shape of enzyme, active site + substrate adjust to fit
Changed environment = improved catalysis
Greater range of substrate specificity
What is optimum pH?
7.4
What happens to enzyme activity at high/low pH?
Activity lost
= tertiary structure changes
What are exceptions to optimum pH?
Pepsin Urease Sucrase Amylase Trypsin Arginase
What is pepsin pH?
2
What is urease pH?
5
What is sucrase pH?
6.2
What is amylase pH?
7
What is trypsin pH?
8
What is arginase pH?
9.7
What does changing pH alter?
Ionisation state of amino acid side chains
What is optimum temp?
37 degrees
Why is little activity at low temp?
Little KE